Re: [PATCH v3 1/3] memblock test: Add test to memblock_add() 129th region

["Huang, Shaoqin" <shaoqin.huang@xxxxxxxxx>]

On 9/18/2022 5:25 PM, Mike Rapoport wrote:
> On Tue, Sep 13, 2022 at 02:41:30PM +0800, shaoqin.huang@xxxxxxxxx wrote:
> > From: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
> >
> > Add 129th region into the memblock, and this will trigger the
> > memblock_double_array() function, this needs valid memory regions. So
> > using dummy_physical_memory_init() to allocate a large enough memory
> > region, and split it into a large enough memory which can be choosed by
> > memblock_double_array(), and the left memory will be split into small
> > memory region, and add them into the memblock. It make sure the
> > memblock_double_array() will always choose the valid memory region that
> > is allocated by the dummy_physical_memory_init().
> > So memblock_double_array() must success.
> >
> > Another thing should be done is to restore the memory.regions after
> > memblock_double_array(), due to now the memory.regions is pointing to a
> > memory region allocated by dummy_physical_memory_init(). And it will
> > affect the subsequent tests if we don't restore the memory region. So
> > simply record the origin region, and restore it after the test.
> >
> > Signed-off-by: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
> > ---
> >   tools/testing/memblock/tests/basic_api.c | 96 ++++++++++++++++++++++++
> >   tools/testing/memblock/tests/common.c    |  7 +-
> >   tools/testing/memblock/tests/common.h    |  3 +
> >   3 files changed, 104 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
> > index a13a57ba0815..7120fd8e47b1 100644
> > --- a/tools/testing/memblock/tests/basic_api.c
> > +++ b/tools/testing/memblock/tests/basic_api.c
> > @@ -423,6 +423,101 @@ static int memblock_add_near_max_check(void)
> >   	return 0;
> >   }
> >   
> > +/*
> > + * A test that trying to add the 129th memory block.
> > + * Expect to trigger memblock_double_array() to double the
> > + * memblock.memory.max, find a new valid memory as
> > + * memory.regions.
> > + */
> > +static int memblock_add_many_check(void)
> > +{
> > +	int i;
> > +	void *orig_region;
> > +	struct region r = {
> > +		.base = SZ_16K,
> > +		.size = MEM_SIZE,
> > +	};
> > +	phys_addr_t new_memory_regions_size;
> > +	phys_addr_t base, size, block_size;
> > +
> > +	PREFIX_PUSH();
> > +
> > +	reset_memblock_regions();
> > +	memblock_allow_resize();
> > +
> > +	dummy_physical_memory_init();
> > +	/*
> > +	 * We allocated enough memory by using dummy_physical_memory_init(), and
> > +	 * split it into small block. First we split a large enough memory block
> > +	 * as the memory region which will be choosed by memblock_double_array().
> > +	 */
> > +	base = PAGE_ALIGN(dummy_physical_memory_base());
> > +	new_memory_regions_size = PAGE_ALIGN(INIT_MEMBLOCK_REGIONS * 2 *
> > +					     sizeof(struct memblock_region));
> > +	memblock_add(base, new_memory_regions_size);
>
> Why don't you simply increase MEM_SIZE, to say 1M?
> This will make all the calculations here way simpler.

Ok. I will increase MEM_SIZE. That can clean the calculation.

> > +
> > +	/*
> > +	 * For the left memory, we split them into small block and add them into
> > +	 * memblock later.
> > +	 */
> > +	base += new_memory_regions_size;
> > +	size = MEM_SIZE - new_memory_regions_size;
> > +	block_size = size / (INIT_MEMBLOCK_REGIONS * 2);
> > +
> > +	orig_region = memblock.memory.regions;
> > +
> > +	for (i = 0; i < INIT_MEMBLOCK_REGIONS; i++) {
> > +		/*
> > +		 * Add these small block to fulfill the memblock. We keep an
> > +		 * interval between the nearby memory to avoid being merged.
> > +		 */
> > +		memblock_add(base + block_size * (2 * i + 1), block_size);
> > +
> > +		ASSERT_EQ(memblock.memory.cnt, i + 2);
> > +		ASSERT_EQ(memblock.memory.total_size, new_memory_regions_size +
> > +						      (i + 1) * block_size);
> > +	}
> > +
> > +	/*
> > +	 * At there, memblock_double_array() has been succeed, check if it
> > +	 * update the memory.max.
> > +	 */
> > +	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
> > +
> > +	/* memblock_double_array() will reserve the memory it used. Check it. */
> > +	ASSERT_EQ(memblock.reserved.cnt, 1);
> > +	ASSERT_EQ(memblock.reserved.total_size, new_memory_regions_size);
> > +
> > +	/*
> > +	 * Now memblock_double_array() works fine. Let's check after the
> > +	 * double_array(), the memblock_add() still works as normal.
> > +	 */
> > +	memblock_add(r.base, r.size);
> > +	ASSERT_EQ(memblock.memory.regions[0].base, r.base);
> > +	ASSERT_EQ(memblock.memory.regions[0].size, r.size);
> > +
> > +	ASSERT_EQ(memblock.memory.cnt, INIT_MEMBLOCK_REGIONS + 2);
> > +	ASSERT_EQ(memblock.memory.total_size, INIT_MEMBLOCK_REGIONS * block_size +
> > +					      new_memory_regions_size +
> > +					      MEM_SIZE);
> > +	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
> > +
> > +	dummy_physical_memory_cleanup();
> > +
> > +	/*
> > +	 * The current memory.regions is occupying a range of memory that
> > +	 * allocated from dummy_physical_memory_init(). After free the memory,
> > +	 * we must not use it. So restore the origin memory region to make sure
> > +	 * the tests can run as normal and not affected by the double array.
> > +	 */
> > +	memblock.memory.regions = orig_region;
> > +	memblock.memory.cnt = INIT_MEMBLOCK_REGIONS;
> > +
> > +	test_pass_pop();
> > +
> > +	return 0;
> > +}
> > +
> >   static int memblock_add_checks(void)
> >   {
> >   	prefix_reset();
> > @@ -438,6 +533,7 @@ static int memblock_add_checks(void)
> >   	memblock_add_twice_check();
> >   	memblock_add_between_check();
> >   	memblock_add_near_max_check();
> > +	memblock_add_many_check();
> >   
> >   	prefix_pop();
> >   
> > diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c
> > index eec6901081af..2de6a2b6efd2 100644
> > --- a/tools/testing/memblock/tests/common.c
> > +++ b/tools/testing/memblock/tests/common.c
> > @@ -5,8 +5,6 @@
> >   #include <linux/memory_hotplug.h>
> >   #include <linux/build_bug.h>
> >   
> > -#define INIT_MEMBLOCK_REGIONS			128
> > -#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
> >   #define PREFIXES_MAX				15
> >   #define DELIM					": "
> >   
> > @@ -84,6 +82,11 @@ void dummy_physical_memory_cleanup(void)
> >   	free(memory_block.base);
> >   }
> >   
> > +phys_addr_t dummy_physical_memory_base(void)
> > +{
> > +	return (phys_addr_t)memory_block.base;
> > +}
> > +
> >   static void usage(const char *prog)
> >   {
> >   	BUILD_BUG_ON(ARRAY_SIZE(help_opts) != ARRAY_SIZE(long_opts) - 1);
> > diff --git a/tools/testing/memblock/tests/common.h b/tools/testing/memblock/tests/common.h
> > index 78128e109a95..ba14dc989ae9 100644
> > --- a/tools/testing/memblock/tests/common.h
> > +++ b/tools/testing/memblock/tests/common.h
> > @@ -11,6 +11,8 @@
> >   #include <../selftests/kselftest.h>
> >   
> >   #define MEM_SIZE SZ_16K
> > +#define INIT_MEMBLOCK_REGIONS			128
> > +#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
> >   
> >   enum test_flags {
> >   	/* No special request. */
> > @@ -104,6 +106,7 @@ void reset_memblock_attributes(void);
> >   void setup_memblock(void);
> >   void dummy_physical_memory_init(void);
> >   void dummy_physical_memory_cleanup(void);
> > +phys_addr_t dummy_physical_memory_base(void);
> >   void parse_args(int argc, char **argv);
> >   
> >   void test_fail(void);
> > --
> > 2.34.1